The study of the gravitational field at infinity has revealed the somewhat unanticipated emergence of infinite-dimensional asymptotic symmetry groups. This phenomenon was exhibited first in the asymptotically flat context in four spacetime dimensions, where the infinite-dimensional BMS\(_4\)  group, which contains the Poincaré group of isometries of Minkowski space as a subgroup, was shown to emerge as asymptotic symmetry group at infinity [1]}, [2]}, [3]}, [4]} (for recent reviews, see [5]}, [6]}). Later and independently, anti-de Sitter gravity in three spacetime dimensions was also shown to exhibit an infinite-dimensional extension of the anti-de Sitter group [7]}.
